HI. I use FieldPoint with Labview to run diesel engine exhaust simulation reactors for the purpose of developing catalytic converters. I am putting together a new system but have encountered a problem with a grounding issue on a FP-TC-K thermocouple input module. I have the FP-TC-K on a FP-TB-10 module. It reads temperatures perfectly fine as long as nothing touches the thermocouple. As soon as I touch the thermocouple with my hand (or a wire connected to ground) the readings jump around. Over 5 seconds it may read: 26.7, 29.5, 22.4, 30.8, 26.1, 33.9, 27.2, 29.2, 30.1, 25.8, 33.6....etc. But when I'm not touching the thermocouple it is easily steady to only two tenths of a degree: 26.14, 26.19, 26.33, 26.23, 26.09, 26.12...etc. OK, so it appears there is a grounding issue somewhere. I tried using both a FP-I601 network module and a FP-2001 network module. Neither solved the problem. I have many of each module: FP-TC-K's and FP-TB-10's. I tried to use many combinations of them, but they all give me the same problem. I connected a FP-TC-120 module and I don't have the problem with that module. It reads the temperature steadily whether or not I am touched the thermocouple. I removed all other modules from the network module, the problem was still there. I am running on a Dell laptop computer using a crossover ethernet cable. The laptop is plugged in. I tried unplugging the laptop from the 120V power and running on battery power, it didn't help. I have an almost identical system running on a Dell duoprocessor desktop about 10 feet away and it runs awesome. Any ideas .....PLEASE...pulling hair out...will be bald soon.... Thanks,Gerry

FieldPoint Family

Grounding issue with FP-TC-K on FP-TB-10

Hi Jeff,

I'm not sure what the outcome was for Gerry S, but I it sounds like you could have a stray current running through your thermocouples. How are you grounding your system?

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FieldPoint Family

Grounding issue with FP-TC-K on FP-TB-10

Re: Grounding issue with FP-TC-K on FP-TB-10